Lubricating oil composition

ABSTRACT

A LUBRICATING OIL COMPOSITION FOR THE HOT ROLLING OF METALS COMPRISES (A) FROM ABOUT 50 TO ABOUT 85% BY WEIGHT OF A NAUTRAL FATTY OIL, (B) FROM ABOUT 0.1 TO ABOUT 10% BY WEIGHT OF AN ALKALINE EARTH METAL SALT OF AN OIL-SOLUBLE SULFONIC ACID AND (C) FROM ABOUT 5 TO ABOUT 49.9% BY WEIGHT OF A MINERAL LUBRICATING OIL HAVING A VISCOSITY INDEX OF AT LEAST 50.

United States Patent 3,776,847 LUBRICATING OIL COMPOSITION James W. Pearson, Weybridge, Gareth G. Price, West Byfleet, and Hugh B. Earps, Wirral, England, assignors to Shell Oil Company, New York, NY.

No Drawing. Filed Feb. 10, 1972, Ser. No. 225,283 Claims priority, application Great Britain, Feb. 16, 1971, 4,735/7'1 Int. Cl. C10m 1/40 US. Cl. 252-33 Claims ABSTRACT OF THE DISCLOSURE A lubricating oil composition for the hot rolling of metals comprises (a) from about 50 to about 85% by weight of a natural fatty oil, (b) from about 0.1 to about by weight of an alkaline earth metal salt of an oil-soluble sulfonic acid and (c) from about 5 to about 49.9% by weight of a mineral lubricating oil having a viscosity index of at least 50.

BACKGROUND OF THE INVENTION It is generally known that in the rolling of metals the roll performance, expressed as tons of metal rolled per roll used, can be improved by using lubricating oils. Roll performance is a measure of the extent of the useful life of a roll. Lubricating oils such as fatty oils and synthetic ester lubricating oils, however, can give rise to difficulties, such as spray-nozzle plugging, uncontrollable slipping on the mill and insuflicient adherence to the rolls, particularly under the severe conditions of the hot rolling of steel.

It has now been found that these disadvantages are overcome and trouble-free operation is obtained with a high roll performance in the hot rolling of steel when the lubricating oil compositions of this invention are used.

SUMMARY OF THE INVENTION The invention relates to a lubricating oil composition suitable for the hot rolling of metals, in particular ferrous metals such as steel. The invention furthermore relates to a process for the hot rolling of metals using the present compositions as such or as aqueous dispersions and to metals worked by means of this process.

These lubricating oil compositions comprise (a) from about 50 to about 85 by weight of a natural fatty oil, (b) from about 0.1 to about 10% by weight of a basic alkaline earth metal salt of an oil-soluble petroleum sulfonic acid and (c) from about 5 to about 49.9% by weight of a mineral lubricating oil having a viscosity index of at least 50.

DESCRIPTION OF THE PREFERRED EMBODIMENTS One ingredient of the lubricating oil composition of the invention is a natural fatty oil. Suitable natural fatty oils can be of vegetable origin and they can be blown or unblown. Representative examples of such oils are rapeseed oil and cotton seed oil. Rapeseed oil is particularly preferred.

A second ingredient of the lubricating oil composition of the invention consists of alkaline earth metal salts of oil-soluble sulfonic acids, in particular petroleum sulfonic acids. Of the alkaline earth metal salts, the calcium salts are preferred. The salts can be neutral or basic, although the basic salts are preferred. Suitable oil-soluble sulfonic acids include naphthalene, benzene, and phenol sulfonic acids, as well as their alkyl-substituted derivatives, such as barium dinonylnaphthalenesulfonate. When the preferred basic salts are used, the basicities may range from 20 to over 1000%, and preferably from 50 to 800%.

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A third ingredient of the lubricating oil composition of the invention is a mineral lubricating oil. Suitable mineral lubricating oils are parafiin base and naphthene base distillate oils having a viscosity index of at least 50, preferably at least 75, and a viscosity between about 6 and 60 cs. at 60 C. They may be blended with synthetic hydrocarbon oils such as polyolefins and/or with synthetic nonhydrocarbon lubricating oils such as ester oils or polyoxyalkylenes such as polyethylene glycols. The lubricant compositions of the invention may contain additional additives, such as anti-oxidants, anti-foamants, anti-corrosion agents and extreme pressure agents. Especially in the hot rolling of steel extreme pressure agents may advantageously be used. Preferred extreme pressure agents are metal hydrocarbylthiophosphates. The metal is preferably a polyvalent metal such as an alkaline earth metal, cadmium, zinc, iron and the like, in particular zinc. The hydrocarbyl group is preferably an alkyl or cycloalkylgroup having up to 30, particularly 3 to 12 carbon atoms. Preferred compounds are zinc dialkyl dithiophosphates in which the alkyl groups are selected from propyl, butyl, pentyl, hexyl, cyclohexyl, octyl, decyl and dodecyl groups. The proportions of the additional additives may range between about 0.1 and 25% by weight, based on the total composition.

The lubricant compositions of the invention may advantageously be used as an oil/water mixture (loose dispersion) in the hot rolling of steel.

EXAMPLE The following lubricating oil compositions were prepared in the proportions in percent by weight (percent w.) given in the table below:

TABLE I Composition A 49% w. MVIN 65 (naphthenic, medium viscosity index, mineral oil, viscosity l4 cs. at 60 C.). 50% w. blown rapeseed oil. 1% w. basic calcium petroleum sulfonate (as a concentrate containing 58%. w. of mineral oil) B 45% w. HVI 65 (high viscosity index mineral oil, viscosity 14 cs. at 60 C.). 50% w. rapeseed oil. 5% w. basic calcium petroleum sulfonate (same as in A). 10% w. HVI 65 (high viscosity index mineral oil, viscosity 14 cs. at 60 C.). w. rapeseed oil. 5% w. basic calcium petroleum sulfonate (same as in A). w. rapeseed oil. 5% w. basic calcium petroleum sulfonate (same as in A).

Oil

Carefully cleaned steel plates are dipped in water and then in oil A at ambient temperatures. Only a few very globules of water remained on the plates, which globules disappeared after standing for an hour. A commercial hot steel rolling lubricant which was analyzed as an ester of a polyol and a C1242 fatty acid left substantial numbers of large globules on the plates, which globules were still present after one hour. Moreover, oil A separated from emulsion in water much more readily than said commercial oil.

The roll performance of aqueous dispersions of oils A-C (within the scope of the invention) and D (outside the scope of the invention) in hot steel rolling was tested on a commercial scale and appeared to be 117,000

tons steel per roll of oils A-C (average) and 98,000 tons 2. The composition of claim 1 wherein said basic salt per roll for oil D (average of 2 trials). Two aqueous is a basic calcium salt. dispersions of commercial hot steel rolling lubricants 3. The composition of claim 2 wherein the basicity of which were analyzed as an ester of a polyol and a C1242 said basic calcium salt is from 50 to 800% fatty acid, and as whale oil, respectively, gave roll per- 4. The composition of claim 1 wherein said mineral formances of about 85,000 tons per roll. Experiments with lubricating oil has a viscosity index of at least 75. an aqueous dispersion of another commercial oil which 5. An aqueous dispersion consisting of the composition was analyzed as an aviation lubricant type pentaerythritol of claim 1 dispersed in water. ester had to be discontinued since excess slipping occurred resulting in loss of mill control. 10 References Cited These data clearly show the advantages of the lubricat- UNITED STATES PATENTS ing oil compositionsof the invention. 2 545 138 3/1951 David 4 We clam as 3,429,815 2/1969 Drake 25256 R x 1. A lubricating oil composition for the hot rolling of steel consisting essentially of (a) from about 50 to about 15 85% by weight of rapeseed oil, (b) from about 0.1 to DANIEL M Puma? Exammer about 10% by weight of a basic alkaline earth metal salt METZ, Asslstant Exammer of an oil-soluble petroleum sulfonic acid and (c) from about 5 to about 49.9% by weight of a mineral lubricating oil having a viscosity index of at least 50 and a -viscosity between about 6 and 60 cs. at 60 C. 

